It is not so much the high gravity that could present a problem, it is more a matter of the alcohol levels. High levels of alcohol may stop your fermentation. The alcohol tolerance for most brewing yeast is at least 8%, Although levels of up to 12% can be produced by some ale strains. I think that scottish ale #1728 will do the job, but if it can't than just pitch some champagne yeast to finish the job. It won't affect the flavor because it has a neutral profile and will ferment the sugars out because of its high alcohol tolerance. Just remember that when brewing high gravity beers you will have to increase Pitching rates proportional to your starting gravity.

Thanks for the reply, i normally only make about 1 pint of starter up for a beer, but intend to double that amount for this one. The beer will ferment down to 9 - 10% alcohol so it sounds like the yeast strain will do the job.I had intended to have a wine yeast handy in case it got stuck but didnt want the flavours this will produce. I didnt know that a champagne yeast would ferment out "clean" so thanks for that snippet of info.